Goralis III
From Star Trek : Freedom's Wiki
Goralis III is the third planet of the Goralis system in the Cardassian Union.
In 2375, the runabout Gander, carrying Lieutenant Ezri Dax and Lieutenant Commander Worf, was destroyed in the atmosphere of this planet following an attack by two Jem'Hadar attack ships. Fortunately, Dax and Worf were able to transport to the planet's surface prior to the starship's destruction.
During their time on Goralis, Worf and Dax's relationship grew to a boiling point, and an argument between the two ultimately led to their sleeping together. This new development in their relationship was cut short, however, when they were captured by the Breen shortly thereafter. (DS9: "Penumbra", "Tears of the Prophets")